全文获取类型
收费全文 | 2502篇 |
免费 | 17篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 110篇 |
金属工艺 | 17篇 |
机械仪表 | 22篇 |
建筑科学 | 28篇 |
矿业工程 | 2篇 |
能源动力 | 48篇 |
轻工业 | 56篇 |
水利工程 | 3篇 |
石油天然气 | 6篇 |
无线电 | 45篇 |
一般工业技术 | 103篇 |
冶金工业 | 1966篇 |
原子能技术 | 28篇 |
自动化技术 | 79篇 |
出版年
2024年 | 2篇 |
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 21篇 |
2019年 | 24篇 |
2018年 | 28篇 |
2017年 | 16篇 |
2016年 | 21篇 |
2015年 | 15篇 |
2014年 | 18篇 |
2013年 | 62篇 |
2012年 | 36篇 |
2011年 | 41篇 |
2010年 | 38篇 |
2009年 | 33篇 |
2008年 | 21篇 |
2007年 | 23篇 |
2006年 | 23篇 |
2005年 | 14篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 8篇 |
1999年 | 55篇 |
1998年 | 597篇 |
1997年 | 318篇 |
1996年 | 249篇 |
1995年 | 154篇 |
1994年 | 108篇 |
1993年 | 108篇 |
1992年 | 23篇 |
1991年 | 42篇 |
1990年 | 36篇 |
1989年 | 22篇 |
1988年 | 28篇 |
1987年 | 33篇 |
1986年 | 31篇 |
1985年 | 35篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 12篇 |
1978年 | 4篇 |
1977年 | 28篇 |
1976年 | 105篇 |
1975年 | 6篇 |
1972年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2521条查询结果,搜索用时 765 毫秒
91.
Multi-Modal Dialog Scene Detection Using Hidden Markov Models for Content-Based Multimedia Indexing 总被引:1,自引:1,他引:0
A class of audio-visual data (fiction entertainment: movies, TV series) is segmented into scenes, which contain dialogs, using a novel hidden Markov model-based (HMM) method. Each shot is classified using both audio track (via classification of speech, silence and music) and visual content (face and location information). The result of this shot-based classification is an audio-visual token to be used by the HMM state diagram to achieve scene analysis. After simulations with circular and left-to-right HMM topologies, it is observed that both are performing very good with multi-modal inputs. Moreover, for circular topology, the comparisons between different training and observation sets show that audio and face information together gives the most consistent results among different observation sets. 相似文献
92.
IT outsourcing is a complex and opaque decision problem. Managers facing a decision about IT outsourcing have difficulty in
framing what needs to be thought about further in their discourses. Framing is one of the most crucial steps of human decision
making and needs to be assisted to better understand a decision situation. In this research, we examine a number of decision
primitives in the context of an IT outsourcing decision situation. We demonstrate how the decision primitives can be employed
so that managers can probe deep to better understand a decision situation and to establish a decision basis. In the organizational
setting, we exemplify the use of the decision primitives in relation to the perceived outsourcing implications for the managers
looking for assistance in accommodating a knowledge management perspective on IT outsourcing. Consequently, we induce insight
and a guideline on how to use knowledge management for effective outsourcing in one of the leading financial institutes in
Europe.
相似文献
Mehmet N. AydinEmail: |
93.
94.
Mehmet Emin Aydin 《Journal of Intelligent Manufacturing》2012,23(4):991-999
Coordination of multi agent systems remains as a problem since there is no prominent method suggests any universal solution. Metaheuristic agents are specific implementations of multi-agent systems, which imposes working together to solve optimisation problems using metaheuristic algorithms. An idea for coordinating metaheuristic agents borrowed from swarm intelligence is introduced in this paper. This swarm intelligence-based coordination framework has been implemented as swarms of simulated annealing agents collaborated with particle swarm optimization for multidimensional knapsack problem. A comparative performance analysis is also reported highlighting that the implementation has produced much better results than the previous works. 相似文献
95.
The influence of duplex surface treatments consisting of a DC-pulsed plasma nitriding process and subsequent coatings of CrN and TiAlN deposited by physical vapor deposition(PVD)on AISI H13 tool steel was studied in this article.The treated samples were characterized using metallographic techniques,SEM,EDS,and microhardness methods.Hydro-abrasive erosion wear tests were performed in a specifically designed wear tester in which the samples were rotated in a wear tank containing a mixture of distilled water and ceramic abrasive chips with a fixed rotational speed.The wear rates caused by the abrasive particle impacts were assessed based on accumulated weight loss measurements.The worn surfaces were also characterized using optical microscopy,SEM,and EDS.Microhardness measurements indicated a significant increase in the surface hardness of the duplex-treated samples.The surfaces of the samples with the TiAlN coating were approximately 15 times harder than that of the untreated samples and 3 times that of the plasma nitrided samples.Hydro-abrasive erosion wear results showed that the duplex surface treatments,especially the CrN coating,displayed the highest erosion wear resistance. 相似文献
96.
To investigate the feasibility of using tissue obtained from human tumor xenografts for in vitro screening of antineoplastic agents, we grew human tumor colony-forming units (CFU) in semisold agar from xenografts serially passaged in nude mice. Growth of human tumor CFU was accomplished from nine xenografts representing five different histological tumor types (ovarian carcinoma, adenocarcinoma of the colon, malignant melanoma, epidermoid carcinoma of the lung, and malignant astrocytoma). Cloning efficiency ranged from 0.04 to 0.1% and showed significant variability both between tumor types and between individual animals bearing the same type of xenograft. A high percentage of tumor CFU was in S phase [47 +/- 20% (S.D.)] as determined by the thymidine "suicide" technique. The number of tumor CFU observed increased linearly with increasing numbers of cells plated. In vitro drug sensitivity of the tumor CFU was assessed to Adriamycin, cis-platinum, and melphalan. The patterns of drug sensitivity were found to be reproducible and stable over a period of 9 months. Drug sensitivity curves to Adriamycin for five xenografts representing four tumor types showed complex patterns with plateau portions similar to those described for tumor CFU from primary tumors. The rank order of sensitivity of the tumors was compared to that of normal granulocyte-macrophage progenitors and, with the exception of the melanomas, was found to correlate well with clinical experience (order of sensitivity = colon less than ovary less than bone marrow). Growth of human tumor CFU from xenografts represents a reproducible and stable means for the study of the biology of tumor CFU and has potential applications as a means for screening new anticancer agents. 相似文献
97.
Aydin Dogan Goktug Gunkaya Ender Suvaci Markus Niederberger 《Journal of Materials Science》2006,41(24):8196-8201
In this study, a non-aqueous method in a simple one pot reaction process was employed to synthesize nano-sized BaTiO3 particles and then electrophoretic deposition technique was employed for thin film coatings. In the first step of the preparation, metallic barium is directly dissolved in benzyl alcohol at slightly elevated temperatures. Then titanium isopropoxide was added following by a solvothermal treatment. At the end of the reaction, nearly spherical BaTiO3 nanoparticles were obtained typically 5 nm in diameter. After establishing the stability of the BaTiO3 suspension in ethanol, electrophoretic deposition process was performed without any additional operation. Alumina with platinum plating was used as substrate. To achieve the optimal process parameters, various voltages were applied by altering the cathode to anode distance as well as deposition time. High voltages application was possible without causing hydrolysis, because of the non-aqueous ethanol medium with higher surface charge of the nanoparticles. The deposited surface coatings were dried in air and sintered at various temperatures. SEM, EDX and XRD analysis were employed for the investigation of the coating. 相似文献
98.
A new approach, called adaptive Q control, for tapping-mode atomic force microscopy (AFM) is introduced and implemented on a homemade AFM setup utilizing a laser Doppler vibrometer and a piezoactuated bimorph probe. In standard Q control, the effective Q factor of the scanning probe is adjusted prior to the scanning depending on the application. However, there is a trade-off in setting the effective Q factor of an AFM probe. The Q factor is either increased to reduce the tapping forces or decreased to increase the maximum achievable scan speed. Realizing these two benefits simultaneously using standard Q control is not possible. In adaptive Q control, the Q factor of the probe is set to an initial value as in standard Q control, but then modified on the fly during scanning when necessary to achieve this goal. In this article, we present the basic theory behind adaptive Q control, the electronics enabling the online modification of the probe's effective Q factor, and the results of the experiments comparing three different methods: scanning (a) without Q control, (b) with standard Q control, and (c) with adaptive Q control. The results show that the performance of adaptive Q control is superior to the other two methods. 相似文献
99.
100.
Numerical and semi-analytical results of the propagation of high-power ultra-short near IR laser pulses propagating in ionizing air are presented. 相似文献